Field of the Invention
The present invention relates to an original transport device and an image forming apparatus, the original transport device being provided with a pair of paper discharge rollers in an original transport path so as to sandwich and transport an original.
Description of the Related Art
Conventionally, in an original transport device mounted on an image forming apparatus, an original is sandwiched by two rollers provided in an original transport path and is transported. In such an original transport device, when the original get jammed to cause a trouble in transport such as a paper jam, the two rollers are separated from each other so that operational efficiency is improved when a user collects the jammed original.
A double-sided original transport device disclosed in JP 2005-335915 A (hereinafter referred to as “Patent Document 1”) includes: a transport unit having a paper discharge roller; and a fixing unit rotatably holding a pinch roller for pressing an original against the paper discharge roller from the lower side. The transport unit has a mechanism to separate the paper discharge roller upward centering the rotational shaft. The paper discharge roller is pressed against the pinch roller by a pressing spring, and separated from the pinch roller by rotating a release lever that is driven by a solenoid. Thus, in the configuration disclosed by Patent Document 1, the paper discharge roller is press-contacted to/separated from the pinch roller by driving the solenoid. Accordingly, in order to maintain either of the above two states, it is necessary to drive continually the solenoid.
For example, if the paper discharge roller is configured to be separated from the pinch roller when the solenoid is turned on, it is necessary to maintain the separate state of the paper discharge roller until the user collects the original. Thus, electrical power supply to the solenoid should not be stopped. Or, if the paper discharge roller is configured to be press-contacted to the pinch roller when the solenoid is turned on, it is necessary to turn on the solenoid when transporting the original, regardless of whether it is a case of single side reading or double side reading. Thus, driving sound of the solenoid is generated. Furthermore, when such a process is performed continuously and with high speed, the solenoid is turned on and off repeatedly, which results in loud noise.
The present invention was made to resolve the above problems, and an object of the present invention is to provide an original transport device and an image forming apparatus with which the operation time of the solenoid can be reduced and energy can be saved.